Mode-Based Beamforming Arrays for Miniaturized Platforms

In this paper, a new and practical mode-based array concept is proposed. The key principle of this mode-based approach is the use of orthogonal radiation modes existing in highly coupled arrays as individual information channels so as to avoid mutual coupling and correlation. Consequently, mode-based arrays can be very compact in size but without suffering undesired effects such as impedance mismatch or pattern distortion. While providing a general theoretical discussion for this mode-based approach, a practical application example, namely, a compact electronically scanning array module is developed. With a suitable signal combining algorithm, the module is capable of forming and full 360^deg scanning of a high-gain radiation pattern in the azimuth plane. An experimental prototype has been fabricated on a traditional printed circuit board to validate the practicability of the proposed concept. Measurement results obtained are in good agreement with theoretical simulations, showing promising potential of mode-based array modules for modern miniaturized wireless devices.